Wireless telegraphy and telephony.



H. ZWAARDEMAKER. WIRELESS TELEGRAPHY AND TELEPHONY.

APPLICATION FILED JULY 23. I918.

Patented. 0st. 15, 1918.

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HENDRIX ZW'AAEDEMAKER, OF UTRECHT, NETHERLANDS, ASSIGNOR TO DE NEDER- LANDSCl-IE THEEMG-TELEIPI-IOGN MAATSCHAPPIJ, 0F UTI-TECHT, NETHERLANDS, A. LIMITED LIABILEIY CGIEPANY OF THE NETHERLANDS.

HIRE LESS TELEGRAPHY AND TELEPHONY.

Specification of Letters Patent.

Patented Qct. is, rare.

application filed July 23, 1918. Serial N 0. 246,385.

To all whom it may concern:

'Be it known that 1, Prof. Dr. HENDRIX Zwaannmmnnu, professor of the University of Utrecht, a subject of the Queen of the Netherlands, residing at Utrecht, in the glProvmce of Utrecht, 1n the kingdom of the Netherlands, have invented certain new and useful improvements in Wireless Telegraphy and Telephony, of which the following is a specification.

The invention relates to further improvements in the system of Wireless telegraphy and telephony, and is based on the observed principle, that the sensitiveness of the thermic telephone, serving simultaneously as detector, can be considerably increased, when it Works with polarization, for instance by pro-heating it by a constant current.

In the accompanying drawing an exampie or" my invention, representing a receiving station, Working on the new principle, is given.

The aerial conductor a is earthed through aprimary coil 0, located in inductive relation to the secondary coil 01, the length of which can be exactly tuned. To the coil d are connected in series the thermic telephone 5 and the battery 6 having for instance a tension of 2 or l volts. sound condenser 7", which can be tuned, may be connected in parallel to the thermic telephone Z The reception by the receiving station of the electric Waves, emanating from the transmitting station, Will besatisfactory and can be distinctly observed by means of the thermic telephone, even when the oscillationsare weal: and heavily damped. It has proved satisfactory, to listen by the thermic telephone at the vertical part of the serial conductor a to which it is connected by one pole, taking the other pole in the hand in order to profit from the action of the human body capacity.

The resistance of the themic telephone can be brought in accordance with the im- F or increasing the pedance of the secondary coil 03. The air space of the thermic telephone should be as small as possible, and generally itsv resistance should be large. For this purpose, a great number of heating conductors are connected in series.

hat I claim is: z

1. An apparatus for wireless telegraphy or telephony, comprising an aerial, a thermic telephone in electric relation to said aerial, and means for imparting polarization to said telephone, irrespective of the action of the aerial.

2. An apparatus for Wireless telegraphy and telephony, comprising an aerial, a thermic telephone in electric relation to said aerial, and means for heating said telephone, irrespective of'the action of the aerial.

3. An apparatus for Wireless telegraphy and telephony, comprising an aerial, a thermic telephone in electric relation to said aerial, and a source of electric current in .series and in permanent circuit with said telephone, to polarize and. heat it irrespective of the action of said aerial.

4. An apparatus for Wireless tele-graphy and telephony, comprising an aerial, a thermic telephone in electric relation to said aerial, and a source of constant electric current in circuit with said telephone, to polarize and heat it Without reference to the action of said .aerial.

,5.-An apparatus for wireless telegraphy and telephony, comprising an aerial, a thermic telephone in electric relation to said aerial, a source of electric current in circuit with said telephone, and a variable condenser included in said circuit in series With the source of electricity, but in parallel With said thermic telephone.

In testimony whereof I have hereunto set my hand.

' PROF. DR. HENDRIK ZWAARDEHAKER. Witnesses:

D. KLEIJN, M. ALVARADO. 

